Slide projector



y 1949. B. J. WOLFE 2,477,107

SLIDE PROJECTOR I Filed Aug. 51, 1946 U] r llllllllgi BERNARD J. WOLFE F l Ihwcutol' w M II I I I t iFiG.3 4 6 UHOI ncu Patented July 26, 1949 UNITED STATES PATENT GFFICE suns raornc'ron- Bernard J- Wolfe, Irondeuuoit, N. assignor to Bausch & L'omb Optical Company, Rochester, N'. Y., a ccrporation of New York. J [application August 31, 19%, Serial No. 694,198

The present. invention rela es to optical apparatus and more particularly to a device for projecting images of transparencies such as slides or mounted films.

It is an object of the present invention to provide a novel device of the above type which is sturdy, easy and convenient to use, and econom ical to manufacture.

It is a further object to provide such a device comprising a readily-demountable housing which upon removal exposes the inner parts of the projector for servicing.

It is-another object to provide such a device in which'the reliability of alignment'of the lenses thereof is unimpaired by the demountability of certain lens-holding parts in the apparatus.

It' is a. further object to provide such a device wherein the means for holding the demountable parts in assembled relation are simple, reliable, and do not require the use of tools to disassemble.

Further objects and advantages will be apparent to those skilled in this art by reference to the following specification and accompanying drawing in which:

Fig. 1 is a vertical sectional view, with parts in elevation,. showing a preferred form of the present invention,

Fig. 2 is an enlarged sectional view taken on the line 2-2 of Fig. 1,

Fig. 3 is a top view of the retainer member for the condensing lenses thereof,

Fig. .4 is a fragmentary top view in section of the separable connection between the housing and base members of the projection device, and

Fig. 5 is a cross-sectional View of the slide carrier mechanism taken on the line 55 of Fig. .1.

In the projection device here disclosed, a base I0 is formed, by any advantageous manufacturing process such as die casting, with a recess H on .its under side and is provided with the pads l2 and 13 attached at front and rear thereto on which the, baserests. Means for elevatingthe front'end of the projection device are provided in the found a base plate l4 pivoted within the recess H to the base ill by the shaft is which is journaled at It and l! in said base. An elevat- 'ing member for thebase plate, such as a cam i8, 'is fixed on the rotatable shaft is within the recess II in a position to contact the upper side of the base plate M. A lever 2| is fixed to the shaft [9 outside of the base It) for actuating the cam. A torsion spring 22, carried by shaft [5, has its ends 23 and 24 bearing, respectively, against the bracket '4! carried by base iii and the base plate [4. r

3 Claims. (oi. 83*251 Above the base iii, a lamp is having a suitable filament 25 is supported with the filament thereof substantially symmetrically disposed normal to the optical axis of the projection device. Means for mounting the lamp 25 are provided in. the form of a lamp socket 27 attached to the lamp bracket iii by any suitable means, not shown. The lamp 25 may be energized from any suitable source of power through the switch 3!]. The bracket 28 is formed integral with the base It] and serves also to support a light shield 29. Light shield 2% may be formed like a chimney to surround the lamp 25 and is suitably attached to the bracket-23 by any desired means such as bolts 3!. Apertures 32 and 33 are provided on opposite sides of the light shield 29 in substantial alignment with the filament 28. Over the aperture 32, a reflector 34 is symmetrically fixed by any suitable means such as the metal clips 35 and a collective lens 36 preferably of heat-resistant or heat-absorbing glass is held symmetrically over the forward aperture 33 in a manner similar to the reflector 3%.

Means for condensing the light rays projected by the lens are provided in the form of a pair of suitable condensing lenses 3'; and 38 located in alignment with the lens 35. The lower edges of lenses 37 and 38 are held in notches Standdfi formed inth-e spaced elements 42 and 3integra1 with bracket l. Bracket ll is made integral with the base iii and its independent rigidity isassured by-the provision of an erect integral rib Moonnecting the upstanding elements 62 and #33 so that the bracket nil is H-shaped inhorizontal section, as shown in Fig. i.

As best shown in Figs. 2 and 3 of the drawing, the condensing lenses 3'7 and it are held in the notches some it by a resilient lens retainer it made of flat spring material. The retainer-i i is shaped somewhat like an arch, the upper portion being perforated to provide parallel slots 45 and it in which the upper portions of the lenses 3? and 3B are positioned. Straight side portions ll and is on the retainer terminate at the bottoms in inwardly-directed hooks 39 and 59 which anchor' under the base i8 through the slots 5! and 51'. Thebreadth of the lens retainer spring 44 and the stiifness of the spring material areso chosen that the upward thrust of the hooks i9 andbt against the base iii presses-the lenses 3? and 38 into the notches 39 and so and securely holds the lenses in erect position.

.A unitary enclosure or housing member 5! formed by any suitable manufacturing process such as diecasting covers the lamp assembly and condensing lens assembly while being independent thereof. The housing comprises the side walls 52 and 53 joined by the front wall 5 3 and rear wall 55 to form a continuous bottom edge in contact with the base H3. A curved roof 55 having ventilating louvers 5'! in the area above the lamp 25 completes the enclosure 5!. An aperture 53 in the front wall 54 in substantial alignment with the condensing lenses 37 and 38 permits the passage of light rays to the transparency.

According to the present invention, means for releasably holding and aligning the housing 51 in proper location on the base It? are provided in the form of a separable joint 58 and a releasable catch 59. The separable joint 58 comprises an outwardly extending horizontal lip 59 of suitable shape and size which may, as shown in Fig. 1, extend integrally from the bottom of the front wall 54. Lip 60 is arranged to engage, for purposes of alignment of the housing 5| on the base I!) along its forward edge, against a crosswise shoulder 5i formed on the boss 62 which may, if desired, be integral with the base Hi. By referring to Fig. 4, it is seen that the shoulder 61 has extensions 53 and 64 disposed longitudinally of the base Ill to form side shoulders for the purpose of transversely locating the housing 5| on the base 10. A horizontal ledge is provided to extend over and confine the lip 60 against the base H! by fixing an overhanging plate or clip 65 of any desired form, by suitable means such as screws 55', to the top surface of the boss 52. Plate 65 may, if found desirable, be made of spring steel thus providing resilient means for holding the lip Bil against the base l0. Y

The releasable catch 53 which together with the lip 66 constitutes the releasable holding means for the housing 5| is fixed to the rear wall 55 thereof. An opening 68 in the base has a shoulder 61 over which the catch 59 engages. The form of the catch 59 may be varied to suit circumstances but as here shown is made of fiat spring material bent into the form of a hook 68 at its lower end. The angular shape of the hook 68 is such that when the catch 59 is in operative position it will effectively urge the bottom edge of housing 5! against the base in while simultane ou'sly urging the lip 65 in a forward direction against the shoulder 6| to maintain proper alignment of the housing 54 with reference to the base 10.

On the outer face of the front wall 54, a lens supporting member 69 is pivotally mounted so as to swing downwardly about a hinge H. The rear face 12 of the member 59 is held in contact with the wall 54 by releasable means of any suitable form such as the spring locking member 73 fixed to the wall 55 at M and having a hole therein engaged by a pin which is fixed to the supporting member 59. Transversely across the face I2, a horizontal open slot 7B is formed for accommodating a slide carrier Ti therein. The usual dual apertures, 78, 19 are provided in the slide carrier T! for the passage of light therethrough when the slide carrier 7'! is in either of its two operative positions in alignment with the condensing lenses 3'! and 38. Dual vertical cavities 89, 8! in which transparencies 82 such as slides or mounted films are held substantially symmetrically over said dual apertures 18, 19 are also provided in the usual way. The slide carrier I! is freely slidable back and forth in slot 15 and suitable resistance to such movement is provided by tension spring H3 which bears against the upper edge of slide carrier 1 1. Downwardly projecting stops 83 are secured to the respective ends of the carrier for limiting its lateral movement.

The lens-supporting member 69 is hollow and is provided with a cylindrical passage 84 in the nose portion thereof wherein a focusing tube 85 is slidably and adjustably held. An objective lens 86 is mounted in the focusing tube 85 for forming an image of the transparency 32 by the light rays which are projected from the lamp 25 through the transparency.

When it is desired to remove the slide carrier H, the locking member 13 is flexed upwardly until the .pin 15 is released therefrom thus allowing the lens mounting member 69 to swing downwardly so that the slide carrier 11 can be removed from the-open slot 15. If it is necessary to remove the housing 5l' for servicing of the optical elements or otherwise, the catch 59 is flexed forwardly by reaching underneath the base 10 and the rear of the housing is thereupon lifted off the base it, meanwhile pivoting the housing 5! about its lip 65. As soon as the catch 59 is free of the base 10, the housing 5| is drawn backwardly to free the lip 65 from the overhanging plate 65 and thereafter the entire housing with the lens-mounting member 69 attached may be lifted off the base ii).

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other forms are possible and that changes may be made in the-proportion of the parts and the arrangement thereof without departing from the spirit of the invention as defined in the appended claims.

I claim: v

1. In a projector having a housing enclosing a light source and condensing lens means and having an aperture in the front wall of the housing in alignment with the lens means, the combination of a hinge mounted on the front Wall beneath the aperture, a tubular lens supporting'member secured to the hinge whereby the member may be selectively moved into engagement with the front wall, the face of the member whichcontacts the front Wall having an open slot formed'therein whereby the front wall coacts with the open slot to form a passageway, a slide carrier movabiy mounted in the passageway, and latch means for holding the member against the frontwall for retaming-the slide carrier in the passagewaywhereby the slide carrier is removably held within the passageway;

2. A projection device comprising a base, a light source supported by the base, light condensing means mounted on the base in operative alignment with the light source, a unitary housing for said source and condensing means, said housing having front, rear, top and side walls, a lip projecting from the bottom of the front wall, an integral boss on said'base, a plate secured to and projecting over the boss,said lip cooperating with the plate on the boss for detachably holding the front end of the housing to the base, latch means for releasably holding the rear end of the housing to the base and a slide carrier and objective lens supported by the front wall of the housing in operative alignment with the condensing means.

3. Inc. projectiondevice the combination of a base, a bracket integrally formed with the base, a light source mounted on the bracket, 'a second bracket integrally formed with the base, said second bracket being H-shaped in horizontal sec- 2,477,107 7 5 s tion and comprising two spaced upright elements REFERENCES CITED connected by an integral Said elements a The following references are of record in the ing spaced pairs of notches, spaced condensing me of this patent: lenses having their lower edges positioned in the respective pairs of notches, a, housing carried by UNHED STATES PATENTS the base for enclosing said light source and Numb r N t lenses, and means on the housing for supporting 439,420 McIntosh Oct. 28, 1890 a transparency opposite an aperture in the hous- 1,579,880 Meissner et a1 Apr. 6, 1926 ing which is aligned with the source and lenses. 2,221,920 Kurtz V- 4 2,275,863 Rauch Mar. 10, 1942 BERNARD J. WOLFE. 2,276,735 Miller Mar. 17, 1942 2,285,915 Dutton June 9, 1942 

